Drying time of screed before leveling compound

First of all, hello to everyone :-)

I have already read a lot in this forum, but this is my first post because I have not found an answer to my current question.

I used screed concrete for the first time 6 days ago. Unfortunately, it did not turn out as level as I had hoped, and now I want to even it out with a self-leveling compound. The thickness of the screed is 7cm. I have read that complete drying takes at least 7 weeks (1 week per cm). Do I have to wait this time or can I already apply the leveling compound now? Or will it seal the surface and prevent any moisture from the concrete from escaping?

We want to lay tiles at the end.

Thanks for your help.

Best regards

Robinson

Hello Robinson

It is advisable to wait with the leveling. The screed should dry out first. If a primer is applied now and another dense layer is placed on the screed, the drying process will be delayed. The drying is largely dependent on the density of the screed and the relative humidity. There is a rule of thumb that says: the first two centimeters one week and the following centimeters two weeks. Before laying the tiles, the screed must definitely be checked for its readiness for covering.

There is a rule of thumb that says: The first two centimeters take one week and the following centimeters two weeks. Before laying the tiles, the screed must be absolutely checked for its readiness for covering.

good evening

we are currently asking ourselves when the installation company can finally lay the parquet?! we don't even know how thick the screed is. according to the installation company, the residual moisture is still far too high.

so first and foremost, we need to find out how thick the screed is in our case. our question to the experts now is especially: does the cited rule of thumb apply to all screeds? that is, cement and anhydrite?

thanks for your info
mk

was hoping for an answer to my question.
can anyone here maybe help me out?
thx

Hello Merkur, Anhydrite and cement screeds each have different drying behaviors; this is based on their different binders; gypsum (anhydrite) in one, cement in the other screed. The parquet installer does well to wait for the covering readiness (= degree of drying); for cement screed, the maximum moisture content at covering readiness for parquet is 2.0%, for anhydrite 0.5%. To control the duration of the interior finishing, it would be interesting to know how thick the screed is. It is, as usual in residential construction, about 40-45mm, which results in a drying time of 3-4 weeks. However, the drying behavior of screeds is determined not only by the composition and screed thickness but also significantly by the installation methods, the start of drying, and the drying conditions (this is a science in itself).

hello again

the publishing company still says it will take a while because the parquet is being laid on an anhydrite screed with underfloor heating and that a maximum residual moisture of 0.3% must be observed?!